Rendered offset to window bounds with Intel OpenGL on Windows

[acarl005]

Description

I ran the hello_triangle example with 1 modification, I disabled the window decorations. The triangle rendered was not aligned with the window bounds. It is slightly down and to the right.

Repro steps

// .\examples\features\src\hello_triangle\mod.rs 
let mut builder = winit::window::WindowBuilder::new().with_decorations(false);

 $env:WGPU_BACKEND = 'gl'; cargo run --bin wgpu-examples hello_triangle 

Notice the black areas and the triangle is cut off at the bottom.

Expected vs observed behavior

This is what the example is supposed to look like

Extra materials

Logs show no validation errors.

This bug looks very similar to #1061. However, the offset in that case was in the opposite direction. Looks like the offset is by the same size though. That only affected the Dx12 backend while this only affects OpenGL. No resizing of the window is required in this case to trigger the bug.

Platform

Windows 10

Selected adapter: Intel(R) HD Graphics 4600
Backend: Gl 
Device type: IntegratedGpu
Vendor ID: 32902
Device ID: 0

I have the latest version of these drivers available from Intel.

[cwfitzgerald]

Oh boy, I have no idea how this works on windows, particularly with OpenGL. Definitely going to need help investigating this.